Orange juice sales ended the 2015-16 Florida citrus season down 5.4 percent — the 14th decline in the last 15 seasons.

But the recent market performance of the state’s signature beverage may have less to do with the consumers’ drink preferences and more with the stark reality that there’s less OJ to buy, said Marisa Zansler, chief economist at the Florida Department of Citrus.

“If we see orange juice sales go down, our first response is, ‘Why are consumers turning away from orange juice?’ We should be asking, ‘What is the impact of availability?’ ” she said. “That’s a large impact that’s often overlooked.”

Without question, OJ production in Florida, which supplies most of the U.S. market, has declined precipitously along with the state’s orange harvest under the impact of the fatal bacterial disease citrus greening.

Florida juice processors produced more than 1.4 billion gallons of orange juice in the 2003-04 season, when the state’s orange harvest reached 242 million boxes, compared to an estimated 445 million gallons with an orange harvest of 81.6 million boxes, according to Citrus Department statistics. Juice companies buy 95 percent of Florida’ orange crop each year.

Greening was first discovered in Florida in 2005 and has since spread to virtually every commercial grove in the state.

Consequently the average price of 100 percent orange juice has increased over that period from $4.43 per gallon to $6.55, department data shows.

“With an increase in price — this is not a luxury good — sales will likely be down,” Zansler said.

OJ sales fell 7.8 percent in the four-week ending Oct. 1 compared to the same week a year ago despite just a 1 percent average price increase over that time, according to the department’s latest sales report. That was the largest sales drop in 18 months.

The September performance sent the 2015-16 seasonal decline down to 5.4 percent. The Florida OJ sales season runs from Oct. 1 to Sept. 30.

OJ continues to have other market issues, including questions raised over its sugar content contributing to the U.S. obesity problem and losing consumers to other beverages, Zansler said.

But the shrinking supply remains the biggest concern.

“Sugar and the consumers’ tastes and preference I don’t believe is the main driving force,” she said of OJ’s sales declines in recent years.

Whatever the reason, the Citrus Department needs to find out more about why consumers are buying less OJ, said Marty McKenna, a member of the Florida Citrus Commission and a Lake Wales-based grower. That’s essential for the time when Florida citrus recovers from greening-induced OJ shortages.

“We want to see where they (consumers) went so we can try to get them back,” McKenna said.

For the four-week period ending Oct. 1, sales of all 100 percent grapefruit juices declined 2.9 percent despite an average 0.4 of a percent price decline to $7.39 a gallon. For the season, sales declined 3.2 percent on a 0.2 of a percent price decline.